That might make for a bit of a quieter trading session later in the day, with the likes of Germany and France sitting out. That might impact liquidity conditions. However, just be wary that most trading exchanges will remain open today - even for the Xetra and Euronext. And with London also open, this won't feel too much of a holiday at least.
But then again, it is not to say that markets have been holding too much conviction in trading this week anyway in Europe.